The therapeutic need to generate nerves, arteries and veins is enormous. Fifty-eight million people in the United States have cardiovascular disease (Ingham, P. W. et al, Genes Devel. 15, 3059-87 (2001)). Another quarter of a million people have spinal cord injuries. In addition, damage to peripheral nerves often results in loss of muscle function, impaired sensation, and painful neuropathies (Evans, G. R. Semin. Surg. Oncol. 19(3), 312-318 (2000)). Progress in addressing these pathologies has been mainly along two fronts—the graft and the bioengineered construct. At present, the “gold standard” in nerve and vessel replacement is still the autologous graft (Evans, G. R. Semin. Surg. Oncol. 19(3), 312-318 (2000)). Understanding how to harness and amplify the regenerative capacities of adult tissues stands to provide answers to many regeneration problems and augment bioengineering solutions (Fuchs, E. et al. Cell 116, 769-778 (2004). To this end, there is a great unmet need to provide mechanistic insight into development and to recover latent capacities for arteriogenic and neurogenic activity.